In general, lithium secondary batteries can be manufactured via various assembling processes and include wound, laminated and stacked batteries. For example, in the case of a laminated lithium secondary battery, electrode slurry containing an electrode active material optionally with a binder and a conductive agent is applied onto a current collector to provide a cathode and an anode individually. Then, the cathode and the anode are stacked on both sides of a separator to form an electrode assembly with a desired shape, and the electrode assembly is inserted into a casing and sealed to provide a finished battery. A lithium secondary battery obtained by the above-mentioned method may cause an internal short circuit between both electrodes due to internal or external factors during the assemblage of the battery, for example, in a step of stacking (laminating) a cathode, a separator and an anode successively. Such an internal short circuit is followed by generation of low-voltage defects after a formation step, which is performed after the assembling step in order to activate a battery by subjecting it to charge/discharge cycles. As a result, the yield of desired finished batteries decreases.